Add API to get KeyCode produced by physical key location.

The physical key location is provided as a location KeyCode pointing to a location on a US keyboard layout.

Bug: 179812917
Test: atest KeyboardLayoutChangeTest
Test: atest android.hardware.input.cts.tests -m
Test: atest inputflinger_tests -m
Change-Id: Ib5ed41890cbbe393ee9ada1a04cbaaf82c9bb1fc